Variation & Adaptation

Question 1

Evolution

Answer 1

a permanent genetic change in a population.

Individuals CANNOT evolve over their lifetime (only populations evolve!)

Populations of the same species that are exposed to different environmental pressures can become so genetically different that they can no longer interbreed; they diverge (split) into two separate species!

Question 1

Evolution can be thought of in multiple ways

Answer 1

-Change over time
-Change in heritable features over time within populations
-The origin of new forms of life (i.e. new species or subspecies)
-Descent with modification (descendents inherit their attributes from common ancestors) - proposed by Charles Darwin

Question 2

Variation

Answer 2

give an individual a better chance of surviving to reproduce will be passed onto offspring.

Question 3

Adaptation

Answer 3

As this trait is passed on through successive generations, the variation will become more and more common in the population.

Adaptations can be visible or invisible differences.

Question 4

Interspecific Variation

Answer 4

variations occur between different species
Eg. humpback vs. orca

Question 5

Intraspecific Variation

Answer 5

variations occur between members of the same species
Eg. ladybug spots

Question 6

Continuous Variation

Answer 6

refers to characteristics like weight or height, which change gradually.
-No distinct categories (variation can exist on a spectrum)
-Controlled by many genes
-Strongly influenced by the environment

Eg. eye colour, hair colour, height, etc.

Question 7

Discrete (Discontinuous) Variation

Answer 7

Distinct categories (this vs. that)
Controlled by a few genes
Unaffected by the environment

Eg. tongue rolling, blood type, etc.

Question 8

Structural Adaptation

Answer 8

physical features of an organism
Eg. Teeth, feathers, scales, talons, shells, needles, etc.

Question 9

Behavioural Adaptation

Answer 9

the way an organism acts or things it does to survive
Eg. hibernation, migration, play dead, etc.

Question 10

Physiological Adaptation

Answer 10

changes or chemical reactions that occur within an organism
Eg. venom, poison, toxins, etc.

Question 11

Sexual Reproduction

Answer 11

• Mixing of genetic information from the parents (male sperm and female egg)
• Sexual reproduction increases the variability in a population (makes the gene pool larger - which is a good thing!)

Question 12

Mutations

Answer 12

Changes in the DNA of an organism. Can be caused by mutagens.
Eg, Color blindess, Sickle cell anemia

Question 13

Natural Selection

Answer 13

Mechanism of evolution. Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success. This process causes species to change and diverge over time.

Question 14

Phenotype

Answer 14

an observable trait, can refer to anything from a common trait, such as height or hair color, to presence or

Question 15

Gradualism

Answer 15

Process of evolution takes place over MANY small steps. The world is much older than previously thought.

Question 16

Overproduction

Answer 16

More organisms are produced than can survive due to limited resources - encourages competition

Question 17

Population Speciation

Answer 17

Individuals within a population vary in their traits (variation), some of which are heritable. This causes very small changes within populations (adaptation), causing the evolution of that species

Question 18

Jean-Baptiste Lamarck

Answer 18

-Believed individual organisms changed in response to their environment, then passed favourable traits to their offspring.

-Use and Disuse

Eg. Giraffes have long necks because they stretched them to reach leaves on tall trees, then passed these long necks to their offspring

Question 19

Charles Darwin

Answer 19

Sailed on the HMS Beagle to Africa, South America, Australia, and the Galapagos Islands to do research.

Credited with the theory of natural selection or “survival of the fittest” which attempts to explain how populations evolve.

Question 20

Descent with Modification

Answer 20

organisms are descended from one or more common ancestors